PRIOR CONCURRENT THERAPY: Biologic therapy: At least 3 weeks since prior immunotherapy and recovered No concurrent immunotherapy Chemotherapy: At least 3 weeks since prior chemotherapy and recovered No concurrent chemotherapy Endocrine therapy: At least 3 weeks since prior hormonal therapy (except hormone replacement therapy for menopause) and recovered No concurrent hormonal therapy except hormone replacement therapy for menopause Less than 14 days of oral or IV corticosteroid use within the past 6 months Less than 30 days of inhaled corticosteroid use within the past 6 months Radiotherapy: At least 3 weeks since prior radiotherapy and recovered No concurrent radiotherapy Surgery: See Disease Characteristics Other: No prior participation in and withdrawal from this study At least 3 months since any other prior chemopreventive therapy and recovered At least 30 days since prior investigational agents At least 2 weeks since prior beta-carotene at 60 mg/day or more No concurrent beta-carotene at 60 mg/day or more No concurrent oral aspirin greater than 100 mg/day No other concurrent investigational agents No concurrent fluconazole or lithium No concurrent chronic NSAIDs or COX-2 inhibitors